Typically, a session initiation protocol (SIP) endpoint registers with a registrar server when the SIP endpoint first join a SIP system. This registration requires that the SIP endpoint transmit the address of record that is to be associated with it. If a SIP endpoint needs to have more than one address of record associated with it, the SIP endpoint must transmit a discrete register request for each address of record. By having to register each address of record, network resources are burdened. In the case of failover, when several SIP endpoints must switch to different registration servers, the burden on the network is especially heavy. As a result, the time it takes to register multiple SIP endpoints after a failover is long and the network's scalability is reduced when several SIP endpoints have multiple addresses of record associated with them.
SIP endpoints typically have multiple SIP addresses of record (AORs) to be registered. Recent technology allows an increasing number of SIP AORs to be registered per SIP endpoint. In startup, failover, and fallback scenarios, a flurry of messages will be sent to a SIP registration server, which will severely limit the scalability and performance of the SIP registration server. Furthermore, failover and fallback will take a much longer time to complete, potentially affecting the availability of SIP registration severs. With frequent registrations, large amounts of CPU processing capacity and bandwidth will be consumed by the single registration of each SIP AOR by a SIP endpoint.